1. Field of the Invention
The present invention relates to a plasma generation apparatus which irradiates a work to be processed such as a substrate with plasma, so that its surface can be cleaned or the surface quality can be reformed, and a work processing apparatus provided with this.
2. Description of the Background Art
A work processing apparatus is known which applies plasma to a work to be processed such as a semiconductor wafer. Thereby, it removes organic dirt from its surface, improves the surface's quality, etches the work, forms a thin film, eliminates a thin film, or conducts such another. A plasma processing apparatus is disclosed, for example, in Japanese Patent Laid-Open No. 2003-197397 specification. A plasma generation nozzle is used which includes an interior electric conductor and an exterior electric conductor which are concentric with each other. Between both electric conductors, a high-frequency pulse electric field (i.e., a microwave) is applied, and thereby, not an arc discharge but a glow discharge is produced so that plasma can be generated. In this apparatus, a processing gas from a gas supply source makes its way from the base-end side to the free-end side while whirling round between the interior and exterior electric conductors. Thereby, denser plasma is generated and radiates from a nozzle attached to the free end toward a work to be processed. This helps secure plasma with a high density under a normal pressure.
However, in the above described prior art, although the plasma generation nozzle's structure is shown, how to obtain stable plasma (i.e., plume) is left out of account. In this respect, there is still room for improvement.